Muwatta Malik 393
موطأ مالك#393SahihYahya related to me from Malik from Nafi that Ibn Umar would never turn around when praying
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Salim al-HilaliMauquf Sahih
In-book reference: 9:68